There is little disagreement that the body’s maintenance and repair systems deteriorate with age, even as there is plenty of disagreement as to why. Stem cells combat the aging process by replenishing old or damaged cells—particularly in the skin, gut, and blood—with a fresh supply to maintain and repair tissue. Unfortunately, new evidence published in the open-access journal PLoS Biology suggests that this regenerative capacity also declines with age as stem cells acquire functional defects.
